Originally Posted by
HarryMann
Also bear in mind that D. P Davies was writing quite a while ago now... technologically speaking.
Yes, and he made a weary aside in the book that some pilots were complaining about the presence of stick-pushers as potentially unsafe and unnecessary technology usurping their authority.
Then, a month after the final edition of the book was published a Trident crew comprised of a senior Captain and two relatively junior co-pilots (both S/O) on climb out from LHR retracted the droops too low and slow, approached stall and inhibited the stick pusher. The result was a full deep T-tail stall, pancaking into a field in Staines and 118 people dead.
[EDIT : On a quick fact-checking browse, I decided to have a look at Wikipedia's entry on BEA548/G-ARPI, and I have to say it's probably one of the most impressively researched articles I've seen on the site.
Now, superficially there are at least as many glaring differences as there are similarities between AF447 and BEA548 - the command gradient was very similar, and both incidents involved a loss of control following inappropriate handling, however the former was cruising, the latter was on climb-out, and while the Trident was probably the most advanced airliner in service at the time, the A330 is something else entirely. However what struck me when looking at the Flight articles in the wake of BEA548 was how similar the questions being asked and the debate over automation and warning systems is.
Check this out (apologies for the C&P, but I'm truly gobsmacked by the similarities - emphasis mine):
From
1972 | 3235 | Flight Archive
Captain Evans agreed that some of the line captains were unhappy about a situation which meant that they had their least-experienced crew member in the right-hand seat and the court heard a particularly strong adverse comment from one captain, made coincidentally only a few hours before the PI accident. "It must be remembered," said Capt Evans, "that the P2-only pilot in the P2 seat was trained as a P2 to exactly the same standard as the pilot who would be new to line operation but who had been cleared both as a P2 and a P3."
Mr Thomas referred to the sequence of warnings which would have illuminated shortly after the operation of the droop lever on the accident flight ... and asked Capt Evans whether he would agree with a remark made earlier by the Commissioner, Mr Justice Lane, that it would be very unlikely that a pilot in this particular circumstance would notice the amber
lights: "Everything would happen so quickly that the stick push would probably be the one thing which would be occupying his attention." "Yes," replied the witness, "I think I would agree with that, the big problem here being that of recognition."
Capt Evans said that he had flown through the accident sequences on both the BEA Trident simulator and the Hatfield rig. "Did you notice the droop lights and the amber lights in that period before the stick shake?" "They
were there but not very meaningful."
...
Spurious shakes and pushes were next considered against the background of a suggestion that Trident crews had become conditioned to regard any operation of either stick shake or push as false. "Do you think that pilots generally had come to regard the stall warning system as one that was liable from time to time to operate falsely?"
"One that was liable to operate falsely from time to time, yes." "One that they may have distrusted?" "I do not think so," replied the witness.
Here's one for the force-feedback/straight to Direct/Manual Trim supporters to think about, also note the trim situation :
The fact that PI was carrying nose-up trim during the accident sequence because the autopilot had been trimming to a speed lower than that which should normally have been demanded was discussed, and Capt Evans said that when he had been in the simulators he had been surprised
at the stick-force required to hold the stick forward. "I found that one held the stick forward in order to increase speed and once it had built up to something of the order of 230 to 240kt, bearing in mind that the aeroplane was trimmed to about 160kt, the pressure on the control column was quite considerable; it was difficult for me to leave one hand available to trim the aircraft out at that point." On his first run on the Hatfield rig, when the pusher was dumped at the third cycle as in the accident, Capt Evans
had not been able to recover the aircraft in the height available. "Was this partly because you found that to get the stick forward required more force than you had expected?" asked Mr Thomas. "It certainly required considerable
force for me," said Capt Evans, adding that he had needed to use both hands.
And from
1973 | 1189 | Flight Archive :
The extent of the dilemma in trying to establish the actions on the flight deck, and the motives for them, is thrown into harsh relief by one paragraph in the report. Discussing the possibility of recovery even as late as the point of the dumping of the pusher, Mr Lane says: "Unfortunately, that way of expressing the matter begs the question. If one could have asked the crew at second 127 why they were not flying a recovery, they would surely have said 'a recovery from what?' "
Plus ça change indeed! ]